<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <video autoplay playsinline muted></video>

  <canvas id="picture"></canvas>

  <button id="takePic" onclick="takePic()">拍照</button>

  <button id="takePic" onclick="downLoad()">保存</button>

  <script src="./demo.js"></script>
</body>
</html>